Sand blasting machine



Oct, 4, 1949. w. WOR'KMAN 2,483,956

SAND BLASTING MACHINE Filed June 9. 1947 INVENTOR 'W.J. WORK/WAN ATTORNEY Patented Oct. 4, 1949 2,483,956: SAND; BLASTING MACHINE.

William J; Workman,. NorthAr-lington; N; J1, as!- signor tozWestern; Electric Company, D1001I10.-- rated, New= York,- N. Y., a corporation of New York ApplicationJ-une- 9 1947, Serial No. 753,408:

This invention. relatesto, sand. blasting. ma. chines, andmore particularlyto anabnasivezoontrol therefor.

Conventional types of. sand blasting machines are employed to condition external surfaces of articles and insuch instances, it is not essential that variable quantities. of. abrasivamaterial be directed toward the articles.v In the present invention the abrasive material is directed through a narrow slot orapertureto remove silver coating material fronraquartz crystalnalong agi'veniline; defined by a. narrow-aperture; in a mask, to divide the silver coating; in twoiparts. It-Lhas; been iound that the narrow aperture; in the mask may become clogged'wit-h the abrasive material creating undesirable-effecton the coated crystals: if the abrasive material is forced ZlIlz greater: quantities than, may he: received: readily in the narrow aperture.

It is the object of the present invention to provide a simple and efficient control for a sand blast unit, in a sand blasting machine, wherein abrasive material of variable amounts may be forced through the unit.

With this and other objects in view, the invention comprises a unit in a sand blasting machine including a nozzle to direct an abrasive material in a given path. A hopper for a supply of the abrasive material has a conduit leadin therefrom to the unit. A valve is actuable to admit air un- 1,

der pressure to the unit, and through th unit and nozzle thereof, to create a vacuum in the unit drawing the abrasive material from the hopper. The salient feature of the invention is a provision of means to admit air to the unit short of the nozzle to reduce the said vacuum to reduce the amount of the abrasive material drawn into the unit. More specifically, this means includes an air line entering the unit adjacent the portion where the vacuum is created and including a valve to admit variable quantities of air at atmospheric pressure into the unit to vary the vacuum therein to vary the amount of abrasive material drawn into the unit. There is also positioned in this airline a gage to indicate the vacuum in the unit.

Other objects and advantages will be apparent from the following detailed description when considered in conjunction with the accompanying drawings, wherein Fig. 1 is a front elevational view of a sand blasting machine embodying the invention, portions thereof being shown in section; and

Fig. 2 is a perspective view of an article which is to be sand blasted by the machine.

1 Claim.. (01.51-8.)

The-sand blasting machine in general is=not' shown' in detailas it is substantially-identical with thesand blasting machine shown inthe oopend ing-application of C; J. Kammerer and A. N; Mace Kinnon, Serial No; 753,443 filed: June 9, 1947; with the power means disclosedinthe copending application of Hi H; Merwin; Serial No. 753,535; filed JuneQ; 1 947, nowP-atent. N 25463895 dated Marclrfi; 1949. H

The article shown: in-Fig; 2" includes a quartz crystal-wafer [t with coatings it of silver; Thecoatings H are to be divided intwo-{parts by the abrasive material t2 forced? through a narrow aperture E i in a mask or'carriagelfii The-upper coating M as shown in- Fig; 2 has been divided":

in two partsby :a groove: l 6.

The-carriage l5 is supported on parallel rods 58; only one of which-is shown in the drawing, these rods being: supported inbearings It: which are carried by the main frame of the machine. A power unit drives a fly wheel 2i which carries a stub shaft 22 connected to one end of a link 23, the other end of the link being pivotally connected to a lever 24. The lever 2t is pivotally supported at 25 intermediate'its ends while its upper end is pivotally connected at 26 to the rods 18. In this manner, the carriage I5 is moved through an operating cycle from its starting or loading position shown in Fig. 1 to a given position to move the article through the path of abrasive material and back to the starting position.

The path of the abrasive material extends vertically from a nozzle 29 of a unit 3!]. The unit 30 may be similar to the conventional sand blasting units in that a vacuum is created therein by air under pressure travelling therethrough to draw the abrasive material into the unit and force it through the nozzle in the given path. A conduit 3!, leading from a hopper 32 which houses the supply of abrasive material l2, has its upper end connected at 33 to the unit 38. A supply line 35 for air under pressure is connected through a valve 36 to an air line 31, which extends to the unit 30 and is connected thereto at 38 in alignment with the nozzle 29. A pull rod 20 is under the control of a treadle M which also 0perates a one revolution clutch (not shown) to connect the power means 20 to the fiy wheel 2|.

The salient feature of the invention includes an air line connected to the unit 30 and communicating with the inner portion of the unit where the vacuum is created. The air line 45 is provided with a valve 46 which may be opened variable amounts to admit air under pressure through the line 45 and into the unit 30. A gage 41 disposed in the line 45 short of the valve 46 indicates the degree of vacuum in the unit 30.

During operation of the sand blasting machine, an article is placed on the carriage I5 over the narrow aperture l4 after which a treadle M is actuated to cause reciprocation of the carriage and to open the valve 36 holding it open during movement of the carriage. The air under pressure entering the unit 30 from the air line 31 will pass through the unit and the nozzle .1

creating a vacuum in the unit to draw abrasive material I2 from the hopper 32 through the conduit 3i and into the unit 30 where the material will be forced through the nozzle as it enters the path of the air under pressure. The amount of abrasive material may be varied by reducing the vacuum in the unit. This is accomplished by adjusting the valve 46 from a closed position to a partially opened position, admitting air at atmospheric pressure in variable amounts to reduce the amount of abrasive material forced through the unit to the article. In this manner, the most eificient results may be accomplished completely severing the coating II on the quartz crystal in two parts without damaging the crystal.

Although specific improvements of the invention have been shown and described, it will be understood that they are but illustrative and that various modifications may be made therein without departing from the scope and spirit of this invention as defined by the appended claim.

What is claimed is:

In a sand blasting machine a unit including a nozzle, to direct an abrasive material such'as sand in a given path, a vacuum chamber, an 35 inlet, a hopper for a supply of the abrasive material, a conduit for the abrasive material connecting the hopper to the abrasive inlet of the unit, a supply line for air 'under pressure, an air line connecting the supply line to the air inlet of the unit, a normally closed valve interposed between the supply line and the air line actuable to open communication between the lines whereby the air under pressure travelling through the unit and out of the nozzle will create a vacuum in the vacuum chamber to draw the abrasive material through the conduit from the hopper where it will be forced through the nozzle by the air under pressure, the quantity of abrasive material being withdrawn from the hopper depending upon the vacuum in the vacuum chamber, an auxiliary air line connected to the auxiliary air inlet, and a valve in the auxiliary air line actuable to admit varied quantities of air at atmospheric pressure into the vacuum chamber between the air and abrasive inlets to vary the vacuum in the chamber to vary the amount of abrasive material drawn into the unit.

WILLIAM J. WORKMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,073,149 Lawrence Sept. 16, 1913 2,388,818 Bick Nov. 13, 1945 2,421,806 Perry June 10, 1947 FOREIGN PATENTS Number Country Date 166,761 Great Britain July 28, 1921 

